Corrections to absorbed dose calculations for tissue inhomogeneities

Abstract

Traditional methods for correcting for the presence of tissue inhomogeneities may produce errors as great as 10% at points within or close to the inhomogeneity. A more accurate method is presented which employs tissue–air ratios raised to some power dependent on the relative electron densities of the inhomogeneities involved. Corrections may be made for points that lie within or below an inhomogeneity as well as for multiple inhomogeneities. Measurements were made in phantoms containing aluminum or cork inhomogeneities. Agreement between measured and predicted results was usually within 2%–3%.